The present invention relates to a silver halide color photosensitive material and, more particularly, to a color photosensitive material having good color reproduction, high sensitivity, and high graininess and stable against processing variations.
Conventionally, the use of an interlayer inhibiting effect (interlayer effect) as means for improving the color reproduction of a color photosensitive material is known.
In a color negative sensitive material, for example, color generation of a red-sensitive layer upon exposure to white light can be inhibited compared to its color generation upon exposure to red light by giving a development inhibiting effect from a green-sensitive layer to the red-sensitive layer. Similarly, a development inhibiting effect from a red-sensitive layer to a green-sensitive layer gives reproduction of green with a high degree of saturation.
When the saturation of three primary colors, i.e., red, green, and blue is increased by using these methods, the hue of a color from yellow to cyanic green becomes unfaithful. As a countermeasure against this drawback, a technique described in Jpn. Pat. Appln. KOKOKU Publication No. (hereinafter referred to as JP-B-)03-10287 is proposed. This technique is to achieve vivid and faithful color reproduction by using a silver halide color photosensitive material comprising, on a support, at least one blue-sensitive silver halide emulsion layer containing a color coupler which generates yellow, at least one green-sensitive silver halide emulsion layer containing a color coupler which generates magenta, and at least one red-sensitive silver halide emulsion layer containing a color coupler which generates cyan, characterized in that the barycentric sensitivity wavelength (barycenter .lambda..sub.G) of the spectral sensitivity distribution of the green-sensitive layer is 520 nm.ltoreq.barycenter .lambda..sub.G.ltoreq.580 nm, the barycentric wavelength (barycenter .lambda..sub.-R) of the magnitude distribution of an interlayer effect given to at least one red-sensitive silver halide emulsion layer from another layer at a wavelength of 500 to 600 nm is 500 nm&lt;barycenter .lambda..sub.-R.ltoreq.600 nm, and barycenter .lambda..sub.G -barycenter .lambda..sub.-R.gtoreq.5 nm.
Unfortunately, a sensitive material thus obtained was unsatisfactory in terms of the graininess of a green-sensitive layer. This is considered to be due to the fact that an interlayer effect donor layer and yellow filter layer cut off light near 500 nm more than needed.
Jpn. Pat. Appln. KOKAI Publication No. (hereinafter referred to as JP-A-)6-175289 has disclosed a silver halide color photosensitive material having a yellow filter layer containing a specific oil-soluble dye and a silver halide emulsion layer which gives an interlayer effect to the red-sensitive layer.
This JP-A-6-175289, however, has not disclosed a method of preventing the interlayer effect donor layer from shielding a green-sensitive layer from light. Also, this photosensitive material has another problem that variations in decoloration of the oil-soluble dye vary the photographic properties.
In the field of color photosensitive materials, it is known that the properties of photographic images greatly improve by releasing a photographically useful silver group imagewise at the same time a silver image is formed.
For example, a DIR coupler releases a development inhibitor by coupling with an oxidized form of a developing agent upon development, thereby achieving functions of, e.g., improving the graininess of a color image, improving the sharpness by an edge effect, and improving the color reproduction by diffusion of the inhibitor to other layers. These functions are described in detail in, e.g., U.S. Pat. No. 4,248,962 and JP-A-5-313322.
As described above, development inhibitor releasing couplers contribute to improvements of the quality and sensitivity of a color image. However, these couplers release a development inhibitor by coupling with an oxidized form of a developing agent and at the same time form an azomethine dye. Therefore, these couplers sometimes have an adverse effect on the color reproduction of a color image. This is a large cause of limitations on the versatility, use amount, and molecular design of these DIR couplers. For example, to give a satisfactory interlayer effect from a green-sensitive layer to blue- and red-sensitive layers, a DIR coupler for forming a magenta generating dye alone does not have enough activity. So, it is necessary to combine a high-activity yellow generating DIR coupler and cyan generating DIR coupler. This is unpreferable in terms of color mixing and variations in development processing conditions.
A method of solving these problems is known which uses a redox reaction with an oxidized form of a developing agent as means for releasing a development inhibitor with no dye formation. Examples are DIR-hydroquinones described in, e.g., JP-A-49-129536 and U.S. Pat. No. 4,377,643; DIR-aminophenols described in, e.g., JP-A-52-57828; p-nitrobenzyl derivatives described in, e.g., EP45129; and hydrazine derivatives described in, e.g., JP-A-8-211542. Unfortunately, compared to the functional couplers described above, these redox compounds generally have low stability with time in a sensitive material and are slow to release a development inhibitor after the redox reaction.
Also, couplers, i.e., non-dye-forming couplers, capable of releasing a development inhibitor by coupling with an oxidized form of a developing agent without essentially forming a dye are described in, e.g., JP-B-52-46817 and U.S. Pat. No. 4,315,070. Furthermore, some couplers, i.e., flow-out couplers, release a development inhibitor by coupling with an oxidized form of a developing agent and at the same time form a dye, but this dye formed flows out into a processing solution during processing of photographs. These couplers are described in, e.g., JP-B-1-52742, JP-A-4-356042, and JP-A-8-44011. However, the former non-dye-forming couplers have low coupling activity and are not stable enough. The latter flow-out couplers tend to lower the interlayer effect when used as a DIR coupler, because a nondiffusible group is introduced into a split-off group. Accordingly, it is being desired to further improve the molecular design of these couplers.